Improvement in cards for liquid compasses



E- S. RITCHIE.

' Card for'Compass.

Patented June 2, 1863.

Irwanlor v UNITED STATES PATENT OFFICE.

EDWARDS. RITCHIE, OF BROOKLINE, MASSACHUSETTS.

IMPROVEMENT IN CARDS FOR LIQUID COMPASSES.

Specificationforming part of Letters Patent No. 38,762, dated June 2, 1863.

To all whom it may concern:

Be it known that I, EDWARD S. RITCHIE, a resident of Brookline, in the county of Norfolk and State of Massachusetts, have invented a new and useful or Improved Card for the Mariners Liquid Com pass; and ldo hereby declare the same to be fully described in the following specification and represented in the accompanying drawings, of which Figure 1 is a top view, and Fig 2 a transverse section, of a compass-card made in accordance with my invention.

In constructing such a card a thin disk or film of mica is to have painted, printed, or otherwise fixed on one side of it a series of cardiual points or divisions, together with such designating marks, letters, or characters as may be desirable. After the same may have become sufficiently dry the whole surface on which the paint may have been applied should be covered with a white paint or varnish or some suitable thin water-proofeement. This having been accomplished, another thin disk or film of mica is to be laid on the paint or cement and pressed firmly against the firstdisk, so as to unite the two together to the exclusion of air between them.

In order to effectually exclude the air, and to produce complete adhesion of the surfaces of the two disks, the second one may be gradually slid upon the first. Next, the two should have I a thin metallic border or edging applied around their peripheries and turned down upon their outer surfaces, the said metallic border serving not only to strengthen the card and pro-- tect it from injury, but to give a finish to it.

If desirable, an eyelet may be inserted in the center of the card, the same being to receive a pivot-bearing, which may be of the ordinary kind and be fixed in place in the usual manner.

In the drawings, a b denote the two disks, while 0 is the metallic border or edging.

A compass-card so constructed has a transparency which enables the cardinal divisions to be readily seen through their disk. The mica, being impervious to water, completely protects the divisions from injury.

Instead of the second plate or backing of mica, some equivalent thereforsuch as a thin film of india-rubber or some other Water-proof material-may be employed; but the mica is preferable on many accounts. The whole,when completed, forms a verylight and excellent operative card.

I claim- The new or improved liquid compass-card, made substantially as hereinbet'ore described.

E. S. RITCHIE.

Witnesses:

R. H. EDDY, F. P. HALE, Jr. 

